Member Since: 12 Dec 2012
Location: Middletown, Rhode Island
Posts: 367
Correct Battery Voltage
My Lr3 4.4 v8 had the HDC fault come up today, so I went to the nearest autozone to have them check my battery. He said it was bad with a 12.6v. I thought 12.6 was good and what we wanted? Anyone? The battery was last changed Jan, 2010, at least thats what the sticker says on the battery.
23rd Jan 2013 9:42 pm
MikeS2005
Member Since: 13 Sep 2008
Location: Midlothian
Posts: 920
Correct voltage
Hi
The correct battery voltage for a LR3 is 14.2 to 15.2 running and drops when lighting and other accessories are turned on.
I would have them check the battery and the alternator as these are prone for not charging properly.
Cheers
23rd Jan 2013 9:49 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
12.6v from the battery is totally fine. Perhaps he did a load test and it came up short or the alternator is suspect?
From a TDV6 D3 but the system is essentially the same:
Robbie wrote:
Good battery is around 12.5v and the D3 alternator peaks at around 15.8v (which is higher than most). You should always see over 12.7v when the alternator is running but it seems to settle around 13v+. Alternator goes to full output not long after start (a few seconds) and pushes out almost full power at idle.
Reasonably new battery in rude health:
About 10 seconds after starting:
About 40 seconds after starting:
Apologies for the poor photo but about 60 seconds after starting as shown on a cheap 12v cigar socket voltmeter rather than a Fluke:
The above are pretty typical for a D3 with a good battery and good alternator. Car had not been driven for a day and temp was about 9 deg C, although it was a little colder overnight. The voltage is regulated by the cars engine management system according to load, charging rate and temperature.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Dec 2012
Location: Middletown, Rhode Island
Posts: 367
My battery is three years old. Is it a good idea to change it even though it reads ok? I got the HDC fault code today. If its not the battery, where should I look next? So far with the new battery no HDC fault. Could the battery be reading false voltage? U checked it at my local napa under load and they said it was a good battery? What to do, hmmm????
Member Since: 12 Dec 2012
Location: Middletown, Rhode Island
Posts: 367
Ivan wrote:
Check/replace your brake light switch. It causes all sorts of funny problems.
HTH
Ivan
I got a new brake switch and installed it today, fingers crossed. I took apart the old one and it had black looking soot everywhere. I took some pics but can't find out how to post them here????[/img]
25th Jan 2013 7:48 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
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Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 26 Mar 2007
Location: Chandler's Ford
Posts: 3464
@Robbie
What is that cigarette lighter voltmeter you have there? The ones on eBay only seem to go down to one decimal place whereas yours goes down to two. Would you mind letting me know where you got yours from, please? Seems surprisingly accurate, too, when compared with your Fluke
Cheers,
Steve2021 BMW iX3 Premier Edition in Carbon Black ⚡️🔌
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9th Feb 2013 3:42 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
It was from a Chinese place on Ebay but they tend to come and go.
The accuracy is great but not too much of a surprise as measuring voltage is a simple task and in truth you would struggle to find a cheap DMM or voltmeter that was not accurate enough at these voltages. The same cannot be said for other measurements such as current, capacitance, resistance etc. Clearly I would not go near hazardous voltages with anything other than a quality product!
If I spot a 2 decimal place one I will post a link.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 04 Dec 2012
Location: Skien
Posts: 19
After a period og electronic "hick-ups" when driving (stereo turning of for 1 sec, brake liht lighting, touch screen turning on by itself), I suspected battery/alternator failure. My battery was reading 12,4 with engine off, over 15 with engine on, and then after putting on a lot of power-eaters (seat heat, front screen ++) the reding dropped to 12 and kept on falling. Conclusion: alternator not charging! (Its a 2005 HSE PP TDV6)
I got a new alternator on my used car warranty! Nice for me! ...and a new battery as well!
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...and a new battery as well!
